In this MWE, I demonstrate my problem:


    % works with extra {...}


    % does not work with extra {...}

Some commands work with extra curly braces, some don't. Why is that, and how can I make them work by preprocessing my arguments when they do have extra curly braces?

  • If you remove the {...} in \dosomethingelse around {#1} it works with the doubled {...} as well. – user31729 Mar 25 '16 at 18:23
  • But then the use case without extra {...} (example 3) will stop working... (it still compiles, but it stops doing what it should, which is breaking the line). – bers Mar 25 '16 at 18:24
  • In my point of view, the excess {....} forms a group that can't be used by the seqsplit command in order to split it – user31729 Mar 25 '16 at 18:31
  • I agree. Is there a way to ungroup this group? – bers Mar 25 '16 at 18:31

If the argument is not empty and starting spaces can be removed, then the following trick helps:


\@firstofone is defined in the LaTeX kernel as:


It grabs the first token as argument and outputs it again, thus it does "nothing". But if the argument is not a single token, but a token group in braces, then one level of braces are removed.

  • Thanks! Can one make this a standalone command such as \removeBraces[1] or so? Then one could call \seqsplit{\removeBraces{#1}} - I don't seem able to put this together. – bers Mar 25 '16 at 19:15
  • 1
    @bers \seqsplit scans the argument without expanding it. When \removeBraces is called, it's already too late.The answer uses \expandafter to expand \@firstofone (requires one expansion step exactly), before \seqsplit scans it argument. – Heiko Oberdiek Mar 25 '16 at 19:45

It mostly depend on what command you're dealing with.

If you have \textit{{xyz}}, the additional braces just add a level of grouping; for \seqsplit it's a completely different ballgame, because this command scans its argument one item at a time and a braced group is a single item.

This is described in the manual of seqsplit, in section 2.3:

2.3 Grouping and Commands

The command \seqsplit does not insert breakpoints between the letters inside braces {...}.

[...(omitted example)...]

The braces around {kahg} prevented a splitting of this group. This effect can be used for typesetting special substrings inside sequences.

Braces have a very important syntactical meaning and should not be used in a casual way.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.